The Atomic Time ( TA for French Temps Atomique ) is a time scale on the atomic second is based. At numerous time institutes around the world, atomic time is usually implemented using cesium atomic clocks . In Germany the atomic time is determined by the Physikalisch-Technische Bundesanstalt (PTB). The atomic time of PTB is called TA (PTB). The atomic times of different time institutes are compared by GPS time comparisons, now increasingly by two-way time and frequency comparisons (TWSTFT). The results will be theInternational Bureau of Weights and Measures (BIPM), which forms a weighted average of them which is the basis of International Atomic Time (TAI) published by BIPM.
Both the earth's rotation and the earth's orbital time around the sun are subject to slight fluctuations according to human time standards and cannot be measured with the necessary accuracy. In order to achieve the accuracy of time measurement required in technology and natural science, the fundamental unit of time, the second , is based today on an atomic natural constant . On the other hand, time scales are of interest in everyday life that run synchronously with the mean solar time , ie that are based on the rotation of the earth. Due to certain irregularities in the rotation of the earth, solar and atomic time are not synchronized. However, the deviation is so small that it does not appear in everyday life. This applies hereCoordinated universal time (UTC), which, like atomic time, is based on the second and, if necessary (based on observations of the earth's rotation ), is synchronized with the universal solar time ( UT1 ) by leap seconds .
| Time / time |
( second )
| Atomiteitskala |
( Seconds )
| Solar time |
( solar second )
| Orbital time |
( ephemeris second )
- Tony Jones: Splitting the second: the story of atomic time. Institute of Physics Pub., Philadelphia, PA 2000, ISBN 0-7503-0640-8 (englisch, Inhalt und Review, National Library Board Singapore 2009).
- Atomic time scales. Physikalisch-Technische Bundesanstalt, accessed on April 14, 2011 .
- Atomic time Displays the atomic time of the Physikalisch-Technische Bundesanstalt